Helmet with lattice liner

ABSTRACT

A helmet is disclosed. The helmet comprises an outer shell defining a cavity to receive a head when worn. The outer shell includes a domed inner surface facing towards the cavity and an opposite outer surface. A liner is disposed in the cavity, the liner having a head facing surface and an outer surface opposite the head facing surface, the outer surface facing towards the domed inner surface of the outer shell. The liner comprises a three-dimensional lattice formed of a plurality of cells and at least one liner skin integrally formed with the three-dimensional lattice, the liner skin forming part of the head facing surface of the liner, the liner skin covering less than an entirety of the three-dimensional lattice so as to define a skinless surface area on the head facing surface of the liner.

CROSS-REFERENCE

The present application claims priority on U.S. Patent Application No. 63/078,090 filed Sep. 14, 2020 and on U.S. Patent Application No. 63/111,171 filed Nov. 9, 2020, the entire disclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to impact protection equipment and, more particularly, to sports helmets and liners for such helmets.

BACKGROUND

Protective helmets are worn during certain sports, such as ice hockey, to minimize the effects of impacts to the head of athletes. Impact protection typically entails absorption of energy resulting from linear and/or rotational accelerations and/or deflection of impacts, amongst others. Internal liners in these helmets help with the absorption of energy caused by such forces. Performance in terms of impact energy absorption may limit the level of comfort of such helmets and/or their liners, and in some instances can result in a bulkier or heavier helmet, or in a helmet that is less breathable that would otherwise be desired. There is an ongoing need for improved protective sports helmets, and more specifically for helmet liners.

SUMMARY

In accordance with one aspect of the present invention, there is provided a sports helmet, comprising: an outer shell including a first shell portion and at least a second shell portion displaceable relative to one another to adjust a size of the helmet; and an energy-attenuating inner liner disposed within the outer shell, the energy-attenuating inner liner including a first liner portion disposed within the first shell portion and at least a second liner portion disposed within the second shell portion, the first and second liner portions being displaceable relative to each other when the first and second shell portions are displaced; wherein the first liner portion and the second liner portion each comprise a three-dimensional lattice formed of a plurality of cells and at least one liner skin integrally formed with the three-dimensional lattice, the liner skin forming an innermost surface of the energy-attenuating inner liner adapted to contact the head of a wearer, the liner skin covering less than an entirety of three-dimensional lattice of each of the first and second liner portions to define exposed regions of the three-dimensional lattice free of the liner skin.

The helmet as defined above and herein may further include, in whole or in part, and in any combination, one or more of the following additional features.

In one particular embodiment, the first liner portion and the second liner portion each define a separate padding forming parts of the energy-attenuating inner liner.

In one particular embodiment, the liner skin extends along a periphery of the first liner portion and the second liner portion.

In one particular embodiment, the energy-attenuating inner liner has a head facing surface, an opposite outer surface and peripheral surfaces extending between the head facing surface and the outer shell facing surface, the head facing surface and the peripheral surfaces defining a peripheral edge of the energy-attenuating inner liner at a junction thereof, the liner skin forming the peripheral edge.

In accordance with another aspect of the present invention, there is provided a protective sports helmet for a wearer's head, comprising: an outer shell defining an outermost impact protection structure of the helmet, the outer shell defining a cavity to receive the wearer's head when the helmet is worn, the outer shell having a domed inner surface facing towards the cavity and an opposite outer surface; and a liner disposed in the cavity, the liner having a head facing surface and an outer surface opposite the head facing surface, the outer surface facing towards the domed inner surface of the outer shell, the liner comprising a three-dimensional lattice formed of a plurality of cells and at least one liner skin integrally formed with the three-dimensional lattice, the liner skin forming part of the head facing surface of the liner, the liner skin covering less than an entirety of three-dimensional lattice such as to define a skinless surface area on the head facing surface of the liner, the liner adapted to at least attenuate an impact energy transferred to the wearer's head from a force received by the helmet.

The helmet as defined above and herein may further include, in whole or in part, and in any combination, one or more of the following additional features.

In one particular embodiment, the skinless surface area is a first skinless surface area, the head facing surface having at least a second skinless surface area surrounded by the liner skin such that the three-dimensional lattice is visible in the first skinless surface area and the second skinless surface area from an interior of the helmet.

In one particular embodiment, the liner skin has a textured surface defining an array of valleys and peaks, a height differential defined between the valleys and the peaks being substantially identical over an entirety of the textured surface.

In one particular embodiment, the liner skin has a textured surface defining an array of valleys and peaks, the textured surface having a maximum thickness differential (MTD) measured from a deepest pit to a highest peak, the MTD times a surface area of the head facing surface of the liner occupied by the skin defines a total texture volume (TTV) including a percentage of volume of material and a complementary percentage of volume of air, the percentage of volume of material being of about at least 60%.

In one particular embodiment, the plurality of cells include a first cell geometry and at least a second cell geometry respectively located in different zones of the liner.

In one particular embodiment, the three-dimensional lattice includes first zones composed of cells having a predominately Voronoi geometry and second zones composed of cells having a predominately serpentine geometry.

In one particular embodiment, the three-dimensional lattice includes a boundary layer surrounding a portion of the liner, the boundary layer being formed of a cell type that differs from a cell type of the lattice enclosed within the boundary layer.

The protective sports helmet as described above and herein, there may also include, in whole or in part, and in any combination, one or more of the following features.

The outer shell has a plurality of shell members movable relative to each other to adjust a size and/or fit of the helmet on the wearer's head.

The outer shell has a front shell member slidably engaged to a rear shell member such that movement of the front shell member and the rear shell member relative to each other adjust at least a longitudinal size of the cavity.

The outer surface of the liner contacts the inner surface of the outer shell.

The outer surface of the liner has a shape complementary to that of the inner surface of the outer shell.

The domed inner surface of the outer shell has areas having a profile protruding towards the wearer's head when the helmet is worn, the liner skin defining areas of the head facing surface radially offset from the areas having the profile protruding towards the wearer's head such that the skinless surface area is tangentially offset from the areas having the profile protruding towards the wearer's head.

A majority of a surface area of the head facing surface of the liner is occupied by the liner skin.

About 58%±5% of the surface area of the head facing surface is occupied by the liner skin.

About 35%±5% of the surface area of the head facing surface is occupied by the liner skin.

About 40%±5% of the head facing surface is defined by the skinless surface area.

The skinless surface area is surrounded by the liner skin such that the three-dimensional lattice is visible in the skinless surface area from an interior of the helmet.

The skinless surface area is a first skinless surface area, the head facing surface having at least a second skinless surface area surrounded by the liner skin such that the three-dimensional lattice is visible in the first skinless surface area and the second skinless surface area from an interior of the helmet.

The liner skin extends along a periphery of the head facing surface, between the periphery and the skinless surface area.

The liner has a peripheral surface extending between the head facing surface and the outer surface, a junction between the head facing surface and the peripheral surface defining a peripheral edge, the liner skin covering the peripheral edge, the three dimensional lattice visible along the peripheral edge on the peripheral surface.

The liner skin protrudes from a surrounding portion of the liner that is in the three-dimensional lattice.

The liner skin has a textured surface defining an array of valleys and peaks, a height differential defined between the valleys and the peaks being substantially identical over an entirety of the textured surface.

The liner skin has a textured surface defining an array of valleys and peaks, the textured surface having a maximum thickness differential (MTD) measured from a deepest pit to a highest peak, the MTD times a surface area of the head facing surface of the liner occupied by the skin defines a total texture volume (TTV) including a percentage of volume of material and a complementary percentage of volume of air, the percentage of volume of material being of about at least 60%.

The percentage of volume of material is between about 60% and about 80%.

The three-dimensional lattice forms at least 90% of the liner.

The three dimensional lattice includes a network of struts interconnected at nodes, the struts having a diameter gradient in a thickness-wise direction of the liner from the outer surface to the head facing surface of the liner, the struts adjacent the outer surface having a smaller average diameter than that of the struts adjacent the head facing surface.

The liner has a peripheral surface extending between the head facing surface and the outer surface, the three dimensional lattice includes a network of struts interconnected at nodes, the struts at the peripheral surface being thicker than the struts within a corpus of the liner between the head facing surface and the outer surface.

The three dimensional lattice includes a network of struts interconnected at nodes, the struts originating from respective ones of the nodes extend away therefrom in different directions, the three-dimensional lattice having a greater proportion of the struts oriented normal to the domed inner surface of the outer shell at a first selected location within the helmet than at a second selected location within the helmet.

The first selected location corresponds to a portion of the liner that is adapted to contact an occipital region of the wearer's head and the second selected location corresponds to a portion of the liner that is adapted to contact a temple portion of the wearer's head.

The liner includes a plurality of paddings forming respective parts of the head facing surface of the liner.

The liner includes at least a front padding adapted to cover at least a forehead and/or a frontal portion of the wearer's head, and a rear padding adapted to cover at least a rear portion of the wearer's head.

The liner has a top padding adapted to cover at least a top portion of the wearer's head.

The liner has a crown padding adapted to cover at least a crown portion of the wearer's head.

The liner has side paddings adapted to cover at least respective side portions of the wearer's head.

The front padding has a first zone defining a layer of the front padding stacked on a second zone of the front padding, the three-dimensional lattice in the first zone having a Voronoi geometry and the three-dimensional lattice in the second zone has a serpentine geometry.

The rear padding has a first zone, a second zone and at least a third zone, each defining parts of the rear padding and extending from the head facing surface to the outer surface of the liner, wherein the three dimensional lattice includes a network of struts interconnected at nodes, the three dimensional lattice in the first zone, the second zone and the third zone having a Voronoi geometry, at least in the first zone the struts being thinner than the struts in the second and third zones.

The top padding has a first zone defining a layer of the top padding stacked on a second zone of the top padding, the three-dimensional lattice in the first zone having a Voronoi geometry and the three-dimensional lattice in the second zone has a serpentine geometry having a stiffness in a thickness-wise direction greater than the three-dimensional lattice in the first zone.

The crown padding has a first zone defining a layer of the crown padding stacked on a second zone of the crowd padding, the three dimensional lattice in the first zone having a Voronoi geometry and the three dimensional lattice in the second zone having a serpentine geometry.

The three-dimensional lattice in the side paddings has a Voronoi geometry.

The side paddings and the front padding are integral such as to form one continuous part of the liner.

The front padding include hinges defined in the head facing surface and in the outer surface, at least part of the hinges in the head facing surface extends transverse to the hinges in the outer surface.

A plurality of liner shims disposed within the cavity, the plurality of liner shims secured to the domed inner surface of the outer shell, the plurality of liner shims contacting the outer surface of the liner.

At least some of the plurality of the liner shims are made of a material denser than the three dimensional lattice of the liner, wherein under a static force applied on the at least some of the plurality of the liner shims, the material compresses more than the liner under the same static force at a force application point, in proportion of their respective thicknesses.

The liner includes at least a front padding adapted to cover at least a forehead and/or a frontal portion of the wearer's head, the frontal padding defining a sweat gutter configured to channel sweat from between the liner and the forehead of the wearer's head when the helmet is donned to a region of the liner adapted to be located on a side of a face of the wearer laterally rearward of a wearer's eye when the helmet is donned, the sweat gutter having: a sweat inlet defined by a segment of the skinless surface area surrounded by the liner skin in the head facing surface, the sweat inlet positioned at a location of the liner adapted to extend along a superciliary arch of the wearer's head, and a sweat outlet defined by in a segment of a peripheral surface of the liner free of liner skin, the segment of the peripheral surface closer from a side of the helmet than from a meridional plane of the helmet.

The sweat gutter is a first sweat gutter, the front padding having a second sweat gutter, the second sweat gutter fluidly connected to the sweat inlet of the first sweat gutter through the front padding, the second sweat gutter having a central sweat outlet defined in another segment of the peripheral surface of the liner located in a zone intersecting the meridional plane of the helmet, the central outlet separated from the sweat outlet of the first sweat gutter by a portion of the liner skin extending on the peripheral surface of the liner between the sweat outlet of the first sweat gutter and the central outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying figures in which:

FIG. 1 is a perspective view of a helmet, according to an embodiment;

FIG. 2 is a partially exploded view of the helmet of FIG. 1 ;

FIG. 2A is a perspective view of an outer shell of the helmet of FIG. 2 ;

FIG. 3 is an exploded view of a liner with paddings of the helmet of FIGS. 1-2 , according to an embodiment;

FIGS. 4A-4B show an example of a lattice structure of the liner of FIG. 3 ;

FIG. 4C shows an exemplary cell unit of a cell of the lattice structure of FIGS. 4A-4B;

FIG. 4D shows another example of a lattice structure of the liner of FIG. 3 ;

FIGS. 4E-4F show another example of a lattice structure of the liner of FIG. 3 ;

FIG. 4G shows a lattice structures arrangement from a portion of the liner of FIG. 3 ;

FIG. 5 is a magnified view of a portion of a head facing surface of the liner of FIG. 3 ;

FIG. 5A is an exemplary cross-section of a skin of the liner of FIG. 3 , according to an embodiment;

FIGS. 6 to 14 are illustrations of exemplary textures of the skin of the liner of FIG. 3 , according to different embodiments;

FIG. 15 is another exemplary texture of the skin of the liner of FIG. 3 , according to a particular embodiment;

FIG. 15A is a magnified view of a cross-section A1 of the texture of the skin of FIG. 15 ;

FIG. 16 is another exemplary texture of the skin of the liner of FIG. 3 , according to another particular embodiment;

FIGS. 16A-16B are magnified views of cross-sections B1, B2 of the texture of the skin of FIG. 16 ;

FIG. 17 is another exemplary texture of the skin of the liner of FIG. 3 , according to yet another particular embodiment;

FIGS. 17A-17B are magnified views of cross-sections C1, C2 of the texture of the skin of FIG. 17 ;

FIG. 18A is a bottom view of the helmet, showing a liner with paddings, according to an embodiment;

FIG. 18B is an exploded view of the paddings of the liner of FIG. 18A, with the paddings lying on a plane;

FIG. 18C is another exploded view of the paddings shown in FIG. 18B, with the paddings lying on a plane;

FIG. 18D is a cross-section view of the liner with the paddings of FIGS. 18A-18C, taken in a meridional plane of the helmet;

FIGS. 18E-18I are cross-sections of the respective paddings of FIGS. 18A-18D;

FIG. 19A is a bottom view of the helmet, showing a liner with paddings, according to an embodiment;

FIG. 19B is an exploded view of the paddings of the liner of FIG. 19A, with the paddings lying on a plane;

FIG. 19C is another exploded view of the paddings of the paddings shown in FIG. 19B, with the paddings lying on a plane;

FIGS. 19D-19G are cross-sections of the respective paddings of FIGS. 19A-19C;

FIG. 19H is another bottom view of the helmet shown in FIG. 19A, with the liner removed; and

FIG. 20 is a magnified view of a portion of a liner of a helmet as shown in FIGS. 1-3 , according to an embodiment.

DETAILED DESCRIPTION

FIGS. 1 and 2 illustrate a helmet 100. In the depicted embodiment, the helmet 100 is an ice hockey helmet, though other types of sports helmets may be contemplated, such as lacrosse helmets, or other protective helmets adapted for protection against impacts (e.g. collisions, projectiles, etc.) directed towards a wearer's head, including linear and rotational accelerations and/or impacts. The helmet 100 is adapted to be worn on a wearer's head.

The helmet 100 includes generally an outer shell 120 and an internal liner (or simply “liner”) 130 disposed within the outer shell 120.

In the depicted embodiment, the outer shell 120 defines an outermost impact protection layer of the helmet 100. In other words, the outer shell 120 may be the impact receiving structure of the helmet 100. The outer shell 120 is a panel-like (or “shield-like”) body. The outer shell 120 is relatively thin as opposed to the liner 130. For instance, the outer shell 120 may be between 5 to 10 times thinner than the liner 130, or even thinner. The outer shell 120 is made of a substantially rigid material (i.e. in comparison with the material of the liner 130), such as plastic materials, for example, without limitations, high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), nylon, polypropylene (PP). Other plastics and/or composites suitable for use as an outer shell of a protective helmet are however also possible. While the outer shell 120 may deflect upon receiving an impact, and may spread the impact force over an area of the helmet 100 that is larger than the point of application of the impact load upon deflection, a majority of the energy absorption capabilities of the helmet 100 are provided by the liner 130.

The outer shell 120 may have a thickness (e.g. in a radial direction, away from the head of the wearer) that varies at selected locations of the outer shell 120. For instance, the outer shell 120 may have zones of increased thickness with respect to other zones of the outer shell 120. Such zones of increased thickness may be selectively located where greater stiffness (or less deflection) may be desirable. For instance, in the depicted embodiment, such zones of increased thickness are located on opposite sides of the helmet 100, close to the wearer's temples (above the ear shield/protectors 127 of the helmet 100). Other locations may be contemplated.

The outer shell 120 of the helmet 100 also includes two or more separate shell portions, that are movable relative to each other (e.g. by slidable displacement or otherwise) to adjust the size and/or fit of the helmet 100 on the wearer's head. As shown the outer shell 120 has a front shell member 120F slidably (slidably or otherwise movably) engaged to a rear shell member 120R, defining an overlapping region of the shell members 120F, 120R, where movement of the shell members 120F, 120R relative to each other may adjust at least the longitudinal size and/or the volume of the cavity 122 (see double-sided arrow in FIG. 2 illustrating direction of adjustment according to this example). Other embodiment of the outer shell 120 may include more shell members. The helmet 100 may include an adjustment mechanism (not shown) to selectively adjust the size and/or fit of the helmet 100 on the wearer's head. Such adjustment mechanism may be actuated to selectively allow and prevent the shell members to move relative to each other. Examples of such adjustment mechanisms and/or movable outer shell members are disclosed in U.S. Pat. Nos. 7,634,820, 7,870,618, 8,095,995, 8,448,266 and 9,526,291, for instance, the entire contents of which are incorporated herein by reference. The outer shell 120 may alternately not be adjustable, such that the outer shell 120 may be made of a single shell member in other embodiments.

The outer shell 120 has an outer surface 121 facing towards an outside environment E of the helmet 100. Decal(s) 121A may be applied on the outer surface 121 of the helmet 100 for branding or aesthetic purposes, for instance. In the depicted embodiment, the outer surface 121 has a generally smooth finish, such that a projectile contacting the outer surface 121 at a relative angle may slip relative to the helmet 100. Such slippage may contribute to an attenuation of the impact energy transferred to the brain, for instance.

The helmet 100 may be secured on the wearer's head during use, via a suitable attachment device 110. The attachment device 110 may not prevent relative movement between the helmet 100 and the wearer's head during impact, though the attachment device 110 may prevent the helmet 100 from being unintendedly removed, for instance as a result of the impact during play. In the depicted embodiment, the attachment device 110 includes chin strap(s) 111 adapted to extend under the wearer's chin. As shown, chin strap(s) 111 is/are attached to the helmet 100, here on ear loops 112 that are attached on opposite sides of the remainder of helmet 100. Other attachment devices or features of such attachment device 110 may be contemplated in other embodiments.

Referring to FIG. 2A, the outer shell 120 defines a cavity 122 to receive the wearer's head and the liner 130. The outer shell 120 has a domed inner surface 123 opposite the outer surface 121. The inner surface 123 faces towards the cavity 122. In the depicted embodiment, the ridges and/or other reliefs of the outer shell 120 define areas of the domed inner surface 123 which have a profile protruding towards the wearer's head (or towards the interior of the helmet 100). As shown, such profiles protruding towards the wearer's head correspond to a complementary recess and/or other reliefs defined in the outer surface 121 of the outer shell 120. In other words, in at least some embodiments, a recess defined in the outer surface 121 of the outer shell 120 defines a corresponding positive reliefs (protrusion) of the domed inner surface 123 when viewed from the inside of the helmet 100. In other embodiments, the domed inner surface 123 may define ridges, recesses or other reliefs that do not define recesses, ridges or other reliefs complementary to that of the profile of the outer surface 121. That is, in some embodiments, such as shown the domed inner surface 123 defines ridges 123A and/or other reliefs, that protrude towards the wearer's head when the helmet 100 is worn. The ridges and/or other reliefs may be for rigidifying the body of the outer shell 120, for aerodynamic purposes and/or or aesthetic purposes. In the depicted embodiment, the outer shell 120 defines a plurality of vent holes VH for allowing outside air flowing in the cavity 122 of the helmet 100, which may contribute to the breathability of the helmet 100 during the activity. In the depicted embodiment, at least part of the vent holes VH are defined along the ridges 123A, though this is only one possibility.

With combined reference to FIGS. 1 and 2A, the outer shell 120 defines arch portions 124, or ear cut outs, on opposite sides of the helmet 100. The arch portions 124 are located between a rear portion of the outer shell 120 and a temple portion 125 of the outer shell 120 adapted to extend over the wearer's temples when the helmet 100 is worn. The arch portions 124 defines an open area on the sides of the helmet 100, around the wearer's ears such that the ears are not covered by the outer shell 120. The arch portions 124 are defined by a peripheral edge 126 of the outer shell 120. In the depicted embodiment the peripheral edge 126 extends discontinuously, with the front and rear shell members 120F, 120R defining respective segments of the peripheral edge 126 at the arch portions 124. The peripheral edge 126 may extend continuously (i.e. not segmented) at the arch portions 124 in other embodiments. The peripheral edge 126 extends from the rear portion of the helmet 100 and contours the arch portions 124 and the temple portions 125. The peripheral edge 126 further extends to the front of the helmet 100, along the wearer's forehead (above the wearer's eyes). In the depicted embodiment, removable ear shields/protectors 127 connect to the outer shell 120 and cover (cover or fill) at least part of the arch portions 124 of the outer shell 120. Other embodiments may not include such ear shields/protectors 127.

The outer shell 120 may be manufactured by molding (e.g. injection molding, thermoforming, etc.), though other manufacturing techniques may be contemplated, such as any suitable additive manufacturing techniques, also referred to as “3-D printing”.

Referring now to FIG. 3 , the liner 130 defines the impact absorbing (or “energy-attenuating”) layer of the helmet 100. The liner 130 defines a substantial spatial volume of the helmet 100, i.e. compared to the outer shell 120. The liner 130 is elastically deformable, and upon elastic deformation, the liner 130 may absorb or at least attenuate the impact energy transferred to the wearer's head from a force received by the helmet 100. As shown in FIGS. 1-2 , the liner 130 includes a lattice structure 140 and skin(s) 150, which will be discussed in further detail below. In the depicted embodiment, the liner 130 is manufactured by additive manufacturing techniques (e.g. sometimes referred to as three-dimensional (3D) printing, selective laser sintering (SLS), fused deposition modeling (FDM), stereolithography (SLA), or multijet modeling (MJM)).

The liner 130 has a head facing surface 131 defining a concavity to receive the wearer's head when the helmet 100 is donned and an opposite outer surface 132 facing towards the inner surface 123 of the outer shell 120. The outer surface 132 may thus be referred to as an outer shell facing surface. In at least some embodiments, such as shown, the outer surface 132 of the liner 130 contacts the inner surface 123 of the outer shell 120 and is secured thereto. In other embodiments, an intermediary component may be disposed between the outer surface 132 and the liner 130. Amongst other possibilities, the outer surface 132 of the liner 130 may have a shape complementary to that of the inner surface 123 of the outer shell 120, which may limit interfacing gaps and maximize a volume of the liner 130 within the cavity 122 while providing compactness of the helmet 100, for instance. As shown, the outer surface 132 of the liner 130 defines recesses 132A and ridges 132B. In the depicted embodiment, such recesses 132A and ridges 132B are configured to mate (mate or register) with a correspondingly shaped portion of the inner surface 123 of the outer shell 120. Some portions of the liner 130 are thinner than others, to accommodate the liner 130 to the profile of the domed inner surface 123 while having a volume of the cavity 122 that is sufficient to fit the wearer's head, yet limiting the bulkiness of the helmet 100. In other words, the outer shell 120 (or helmet 100 as a whole) may remain visually “small”, or “close” to the wearer's head, which may be considered more aesthetic in the market.

With continued reference to FIG. 3 , the liner 130 has a plurality of paddings forming respective parts of the inner surface 131 and/or outer surface 132 of the liner 130. In the depicted embodiment, the liner 130 has a front padding 130F adapted to cover at least a forehead and/or a frontal portion of the wearer's head, a top padding 130T adapted to cover at least a top portion of the wearer's head, a crown padding 130C adapted to cover at least a crown portion of the wearer's head, a rear padding 130R adapted to cover at least an occipital (or rear) portion of the wearer's head, and side paddings 130S adapted to cover at least respective side portions of the wearer's head. The number, position and/or shape of the paddings may be different than those shown in FIG. 3 , in other embodiments. Having a liner 130 with a plurality of paddings such as shown may facilitate the manufacturing of the liner 130 or its assembly within the outer shell 120, and/or the adjustability of the helmet 100 (in size and/or dimensions) to fit the wearer's head, whether or not the outer shell 120 is adjustable, as discussed above.

The plurality of paddings (130F, 130T, 130C, 130R, 130S) have a peripheral surface 133 extending between the inner and outer surfaces 131, 132 thereof. At least part of the peripheral surface 133 of adjacent ones of the paddings (130F, 130T, 130C, 130R, 130S) face each other. In at least some embodiments, at least part of the peripheral surface 133 of adjacent paddings may contact each other when assembled in the outer shell 120. As shown, at least part of the peripheral surface 133 of adjacent paddings have a complementary shape adapted to mate and/or interlock with each other, which may allow continuity between the adjacent paddings and/or limit gap(s) (space) between such adjacent paddings. Alternately, the liner 130 may be manufactured as a single padding in other embodiments.

In certain embodiments, it is desirable to minimize the number of joints between the plurality of paddings 130F, 130T, 130C, 130R, 130S, so as to maximize comfort. However, preferably these joints or “seams” between adjacent paddings are positioned such that they are not located in areas of the liner that have the greatest impact on the comfort of the wearer—such as the front padding 130F which comes into contact with the wearer's forehead, and the side paddings 130S which come into contact with the wearer's temples. Accordingly, these joints or seams are best positioned outside of these regions.

Similarly, if any of the plurality of padding portions 130F, 130T, 130C, 130R, 130S which make up the liner are formed first as a flat component, it may be necessary to integrate therein ‘breaks’ or creases in an inner and/or an outer surface of the liner portions. Such breaks on one or both sides of the padding section allow for a substantially seamless surface on the inside of the liner padding, particularly in critical comfort regions as noted above (e.g the forehead and/or temple region, for example), while preventing wrinkles in the padded section. As it will be appreciated by one skilled in the art, if a flat padding section is curved, one side will need to elongate (e.g. have a greater radius) and the other side will need to shorten (e.g. have a smaller radius). Thus, if one of the padding portions 130F, 130T, 130C, 130R, 130S is first produced as a flat padding and subsequently needs to be curved such as to complement the curve on the inside of the outer shell of the helmet into which it is received, the padding portion in question can be designed such that the radially outer surface of the padding fits tightly to the curve of the inner surface of the helmet shell, in which case the breaks between blocks or elements of the padding portion will occur on the radially inner side of the pad. Alternately, the padding portion can be designed such that the radially inner surface of the padding is substantially un-broken by breaks or creases, in which case the breaks between blocks or elements of the padding portion will occur on the radially outer side of the pad. This later alternative is preferred, when possible, as it will improve fit with the wearer's head and thus improve comfort. In certain circumstances, however, in order to achieve or match a more complex three-dimensional curved surface within the inner cavity of the helmet sell, one or more of the padding portions 130F, 130T, 130C, 130R, 130S may need to include breaks, creases and/or cut-outs on both its radially inner side and its radially outer side, albeit at different locations within the padding portion.

Typical liners may be made of foam and other energy-absorbing materials, such as ethylene-vinyl acetate (EVA), vinyl nitrile (VN), polyurethane (PU), expanded polypropylene (EPP), D30™ (material commercialized by D30 Lab), or other impact absorbing material, or a combination of different materials, including a combination of foam to meet impact management requirements, which may be based upon standardized requirements. Although one of the main purposes of a helmet is to protect the wearer's head, helmets may also have an aesthetic aspect. Bulky helmets may be less desirable and/or appealing in the market. As such, there may be a space/volume limitation within the helmet envelope to have a liner 130 meeting a desired level of impact energy attenuation, which may be imposed by standardized impact management requirements. Although some typical foam liners may provide suitable protection against impact, such foam liners may tend to be heavy and have limited breathability and sweat management capabilities, which may affect the wearer's comfort. The liner 130 according to the present disclosure includes a lattice structure 140. In at least some embodiments, the lattice structure is produced using additive manufacturing technique (3-D printing). As can be seen at least in FIGS. 1-3 , a majority of the liner 130 is made of lattice structure 140. For instance, in some cases, from 75% to 99% of the liner 130 is made of lattice structure 140, and in some cases from 85% to 99%. In some cases, at least 90% of the liner 130 is made of lattice structure 140, in some cases, at least 95% and in some cases at least 98%. As described in further detail below, the lattice structure 140 forming the liner 130 may have a single cell geometry, lattice cell types, and/or sizes, etc. or having a number of different cell geometries, lattice cell types, and/or sizes, etc., depending on the embodiments. The remainder of the liner 130 may be made of the skin(s) 150 (discussed later) or other structures/materials. For instance, such other structures may include connector interfaces, fasteners or other types of connectors forming an integral part of the liner 130, whether or not made of the same material, and adapted to interconnect adjacent paddings (130F, 130T, 130C, 130R, 130S) of the liner 130, and/or connect/secure the liner 130 to the outer shell 120 or other components of the helmet 100 (e.g. communication devices, data transmitters, load cells, sensors, tracking devices), for instance. In some cases, components such as connectors, fasteners, etc. may be embedded (or encapsulated) into the liner 130 and still considered as part of the spatial volume of the liner 130.

FIGS. 4A to 4G illustrate examples of the lattice structures 140 which define parts of the liner 130 as described herein. The lattice structure 140 may include a network of struts 141, which may extend in random or predetermined directions to define rigidifying members of the lattice structures 140. The struts 141 may be tube-like structures or solid, depending on the embodiments. The struts 141 may have constant or different lengths, varying or constant cross-sections along their respective length, and/or different or constant thicknesses (dimension normal to their length) depending on the embodiments.

The example of FIGS. 4A-4B is a three-dimensional lattice structure 140 having a Voronoi cell geometry, with such name derived from the Voronoi diagram, which may also be referred to as a Dirichlet tessellation. The lattice structure 140 having such Voronoi geometry has struts 141 interconnected at nodes 142 and forming sides of convex polygons in a plurality of planes, with such polygons containing only one generating point and every point from a given polygon being closer to its generating point than to any other points. The convex polygons define faces of three-dimensional cells 143, which may be defined by a number of cell units 143A having an open volume comprising a plurality of strut segments 141A originating from a central nod 142, with each strut segments 141A extending away from the nod 142 in respective directions. An example of such cell unit 143A is illustrated at FIG. 4C. The exemplary cell unit 143A has a volume having a tetrahedron geometry. The tetrahedron geometry of FIG. 4C is a regular triangular based pyramid geometry (pyramid with a triangular base and sides of equal edge length). The sides of the tetrahedron may be unequal and/or vary within the lattice structure 140. A plurality of such cell units 141A, whether or not of the same dimensions, may be stacked one on another such that the opposing strut segments 141A of two adjacent cell units 143A may extend concentrically, thereby forming a continuous strut/link between the central nod 142 of these two adjacent cell units 143A. The three-dimensional cells 143 of the lattice structure 140 may thus include part of the volume of a number of adjacent cell units 143A connected to each other to form parts of the convex polygons. The configuration of the struts 141 of the lattice structure 140, including their density, sizes, dimensions and orientations may affect the material properties, which may be homogeneous in some embodiments, and the performance of the lattice structure 140 in terms of impact energy absorption/attenuation, resiliency, etc.

In the depicted embodiment, the volume within the lattice structure 140 that is not occupied by struts 141 is open (air), which may be desirable for breathability and comfort, though encapsulated gases or other materials may form at least part of such volume. The open architecture of the lattice structure 140 may provide more comfort to the wearer of the helmet 100 than other helmets with typical foam liners, as allowing more air to flow throughout the helmet 100 and/or providing a lighter liner structure in some embodiments, for instance.

Other cell geometries may be contemplated. For instance, as shown in FIG. 4D, the lattice structure 140 may include a honeycomb structure having struts 141 joined at nodes 142 and forming sides of pentagons in at least one plane. Other geometrical shapes may be contemplated, such as hexagons, heptagons, octagons, etc. In a particular embodiment, such honeycomb structure may include struts twisted along their length.

The example of FIGS. 4E-4F is another cell geometry which may be used to form part or all of a section of the lattice structure 140. The S-shaped honeycomb cellular structure, which may also be referred to herein simply as a serpentine geometry, includes at least one serpentine ribbon 135 that forms at least part of the liner 130, or at least part of one (or more) padding within the liner 130. FIGS. 4E-4F show a segment of a ribbon-like body 135 (or simply “ribbon”). The ribbon 135 has a width W, a thickness T and a length L. The width W is defined from one edge 135E to an opposite edge 135E. The ribbon 135 defines a series of loops, here evenly spaced (i.e. having a radius of the individual loops that is the same or about the same) and having a repetitive shape. For a given liner section, padding or padding zone having lattice structure with the serpentine geometry, a majority, e.g. more than 50%, in some cases at least 75%, or in some cases at least 90%, of the lattice structure 140 with the serpentine geometry has evenly spaced loops of ribbon(s) 135. In some cases, the radius (or spacing) may vary slightly, due to the curvature of the liner 130 (or padding), for instance. The serpentine like ribbon 135 has a plurality of ribbon segments disposed side by side and connected to each other at a number of discrete tangent points along its/their length L. As shown in FIG. 4E, a first ribbon segment 135A is connected to a second ribbon segment 135B at least at two locations along their respective length L, where the loops of adjacent ribbon segments 135A, 135B are tangent to each other.

In FIG. 4F, the ribbon 135 is shown relative to a head form HF, which may represent the wearer's head. As shown, the ribbon 135 extends in a plane radially offset (and/or parallel) to the head form HF. The edges 135E define respectively a head facing edge and an opposite shell facing edge, named with reference to the orientation of the ribbon 135 relative to the outer shell 120 and the wearer's head where such ribbon 135 forms part of the liner 130.

The ribbon 135 is relatively thin, i.e. substantially thinner than the width W of the ribbon 135, as shown in this embodiment. The ribbon 135 is at least three times thinner than its width W in at least some embodiments (e.g. between 3 and 20 times). In some cases, the ribbon 135 may be between 3 and 10 times thinner than its width W, and in some cases even thinner. The thickness T may be adjusted based on, or depend on, impact requirements, and/or desired characteristics of the liner 130 based on impact location. The width W of the ribbon 135 may vary along its length L. This may result from the liner 130/padding(s) having a non-constant thickness, as discussed herein. For instance, in a particular embodiment, the minimum value of width W of the ribbon 135 within the liner 130 is 5±2 mm. In the depicted embodiment, the ribbon 135 is perforated across its thickness T. As shown, the ribbon 135 has an array of spaced apart perforations 135P (or holes), with some perforations 135P open at the edges 135E along the ribbon 135 (see toothed edges 135E) where the perforations are not fully defined (surrounded) by the material of the ribbon 135). When compressed in the widthwise direction, the ribbon 135 may bulk (and/or otherwise deform, such as by bending, shearing, etc.). The ribbon 135 is resilient, in that after compression, the ribbon 135 may recover its uncompressed shape. Deformation of the ribbon 135 may absorb at least partially the impact energy from an impact force received on the helmet 100.

FIG. 4G shows the serpentine like ribbon 135 of the cell structure 140 of FIGS. 4D-4F having a boundary layer (or “cage”) 136 of another type of lattice structure 140. As shown, the ribbon(s) 135 are enclosed (or “sandwiched”) between boundary layers 136 on the edge sides of the ribbon 135. In the depicted embodiment, the boundary layers 136 has the honeycomb geometry discussed above with reference to FIG. 4D. In the embodiment shown, the edges 135E of the ribbon(s) 135 are connected to respective boundary layers 136. Such boundary layers 136 may facilitate the manufacturing of a liner/padding having the lattice structure 140 with the ribbon 135. The boundary layers 136 may facilitate a transition between the lattice structure 140 having the ribbon 135, and another lattice structure 140 (e.g. Voronoi) within the liner 130 as juxtaposed layers/zones of different lattice types. The boundary layers 136 may provide better continuity between juxtaposed layers of different lattice structures 140 having a less compatible topology, for instance where transition between two lattice structures 140 with different geometries may not be smooth enough or provide a desired material continuity.

The lattice structure 140 may be considered as the primary impact energy absorbing portion of the liner 130. A rigidity and damping of the lattice structure 140 may allow for absorption/attenuation of impact energy transferred to the wearer's head. In some embodiments, the configuration of the lattice structure 140 forming at least part of the liner 130 and obtained via additive manufacturing technique may be computer generated using algorithms and optimized, selectively (manually) or algorithmically, to obtain a desired stiffness, resilience and/or damping, whose properties may be selected based on the impact load cases and position of the so-manufactured lattice structure 140 within the liner 130 or helmet 100. As described in further detail below, at least some zones (zones or sections) of the liner 130 or zones (zones or sections) of a padding (130F, 130T, 130C, 130R, 130S) forming the liner 130 may have a lattice structure 140 having different cell geometries and/or different material and/or mechanical properties, including those discussed above, with such zones defining layers (or portions at selected locations) within the liner 130 in some embodiments.

Direct contact between portions of the lattice structure 140 and the wearer's head can, in some instances, cause undesirable discomfort. This may be a result of the density and/or stiffness of the lattice structure 140, rigidity of struts 141 or edges of the lattice structure 140 (e.g. edges 135E), and/or the discontinuous nature of the lattice structure 140, for instance. The liner 130 therefore includes one or more skins 150 which are adapted to contact the wearer's head when the helmet 100 is worn. The skin 150 (which may be referred to in the singular for ease of explanation, but it is to be understood that there may in fact be two or more skin portions which collectively make up the totality of skin 150) is defined on the head side of the liner 130, that is the side of the liner 130 facing the wearer's head. FIG. 5 illustrates a magnified view of a portion of the liner 130 in accordance with one embodiment. In the depicted embodiment, the skin 150 is integrally formed with the lattice structure 140. In other words, the lattice structure 140 and the skin 150 are formed as a continuous, and monolithically formed, part. In other embodiments, the skin 150 may be attached (permanently or removably) to the head facing surface 131 of the liner 130. In such other embodiments, the skin 150 may be referred to as comfort paddings.

The skin 150 is a sheet-like portion of the liner 130 overlaying portions of lattice structure 140 forming the liner 130. The skin 150 may overlay and merge with an underlying portion of the liner 130 defined by the lattice structure 140 at selected areas of the head facing surface 131. The skin 150 may provide a more even surface to contact the wearer's head than the surrounding lattice structure 140. The skin 150 defines a non-interrupted surface portion of the head facing surface 131 in at least two directions taken along the head facing surface 131. As shown, the skin 150 provides a material continuity in at least two direction along the head facing surface 131 that is greater than that of the lattice structure 140 for a correspondingly sized surface area (an equivalent or baseline surface area). In the depicted embodiment, the skin 150 may be viewed as a non-lattice portion of the head facing surface 131. The skin 150 may provide at least some impact energy attenuation in addition to providing greater comfort for the wearer. In the depicted embodiment, the head facing surface 131 of the liner 130 has a surface area occupied by the skin 150 and a skinless surface area. The skinless surface area define exposed regions of the three-dimensional lattice structure 140 free of the skin 150. Having such skinless surface area(s) may provide more breathability than a liner 130 having a head facing surface 131 fully (or substantially, e.g. 98%) covered by a skin 150. Limiting the surface area occupied by the skin 150 may provide a lighter and/or thinner overall liner 130 in some cases.

In some cases, the skin 150 may provide protection against scalp lacerations or friction of the lattice structure 140 on the wearer's head when the liner 130 shifts relative to the wearer's head (e.g. when the helmet 100 is impacted). In some cases, the skin 150 may be located at selected areas where such scalp lacerations may be more prone to happen, for instance in areas where the profile of the inner surface 123 of the outer shell 120 protrudes inwardly towards the wearer's head (e.g. ridges for aerodynamic purposes and/or structural strength purposes). For instance, in some embodiments, these areas may correspond to ridges and recesses 132A, 132B defined in the outer surface 132 of the liner 130 (see FIG. 3 ). As such in at least some embodiments, the skin 150 defines areas of the head facing surface 131 that are radially offset (relative to the outer shell 120) from the areas of the domed inner surface 123 having a profile protruding towards the wearer's head. As such, in some embodiments the skinless surface area(s) is/are tangentially offset from the areas of the domed inner surface 123 having a profile protruding towards the wearer's head.

In an embodiment, a majority (but less than an entirety) of the surface area of the head facing surface 131 of the liner 130 is occupied by the skin 150, either as one continuous piece of skin, or distinct patches of skin 150 at selected locations on the head facing surface 131. For instance, in some cases, between 30% and 75% of the surface area of the head facing surface 131 of the liner 130 is occupied by the skin 150, and more particularly, in some cases, between 30% and 60%. In a particular embodiment, 55%±5% of the surface area of the head facing surface 131 is occupied by the skin 150. In another particular embodiment, 35%±5% of the surface area of the head facing surface 131 is occupied by the skin 150. It may be desirable to have least 40% of the head facing surface 131 as a skinless surface area, which may be more comfortable while maintaining a suitable level of breathability. The proportions/ratios discussed above may be different when considered on a per padding basis, in embodiments where such paddings (130F, 130T, 130C, 130R, 130S) are present. For instance, in an embodiment, on the portions of the head facing surface 131 defined by the respective paddings (130F, 130T, 130C, 130R, 130S), the proportion of skinless surface area is as follows:

Crown padding 130C 60% ± 5% Top padding 130T 42% ± 5% Side paddings 130S 58% ± 5% Rear padding 130R 65% ± 5% Front padding 130F 65% ± 5%

In another embodiment, the portion of the head facing surface 131 defined by the respective paddings (130F, 130T, 130C, 130R, 130S), the proportion of skinless surface area is as follows:

Crown padding 130C 34% ± 5% Top padding 130T 53% ± 5% Rear padding 130R 26% ± 5% Front padding 130F/ 34% ± 5% Side paddings 130S

In the depicted embodiment, the skin 150 protrudes from an adjacent portion of the liner 130 that is in lattice structure 140. In at least some embodiments, the skin 150 may have at least part of its radial dimension (i.e. thickness), taken in a direction normal to the head facing surface 131, defined radially inward (toward the interior of the concavity receiving the wearer's head) from an adjacent portion of the head facing surface 131 of the liner 130. In a particular embodiment, an entirety of the radial dimension of the skin 150 may be defined radially inward from an adjacent portion of the head facing surface 131. In other words, parts of the head facing surface 131 defined by the skin 150 may be radially offset relative to adjacent skinless portion(s) of the head facing surface 131 (i.e. adjacent exposed regions of the three-dimensional lattice). The skin 150 may form an innermost (radially, i.e. normal to the wearer's head) surface portion of the liner 130. The skin 150 may form a friction layer of the liner 130 to partially adhere to the wearer's head with the adjacent lattice structure 140 at the head facing surface 131 not contacting the wearer's head. As such, the skin 150 may define a bearing (bearing or friction) surface of the liner 130 on the wearer's head. In some cases, when the helmet 100 is worn, the lattice structure 140 may not contact the wearer's head, or at least contact the wearer's head with less pressure than the skin 150.

As shown in FIG. 5 , and as better seen in FIG. 5A, the skin 150 includes a textured surface 151. The textured surface 151 is adapted to contact the wearer's head. FIG. 5A shows a cross-section of the skin 150 with the textured surface 151. The textured surface 151 is defined by an array of pits/valleys 152 and peak/ridges 153. In the depicted embodiment, the pits/valleys 152 and peak/ridges 153 all have the same (substantially the same, ±2%) height differential, this is only one possibility. The textured surface may control, limit and/or minimize slip between the wearer's head and the liner 130, which may be due to sweat, depending on the texture geometry. Less slippage may provide greater comfort for the wearer in some cases. However, comfort may be considered as an equilibrium between minimal required friction to limit slip due to sweat for stability of the helmet 100 on the wearer's head, and limited abrasiveness of the texture. While too much grip may cause undesirable discomfort to the wearer (e.g. by pulling hairs, punctual pressure points felt on the head where pressure exerted on the wearer's head is insufficiently dispersed/uniform on the head interfacing zones), too much slippage may cause undesirable discomfort to the wearer (e.g. unstable helmet on the head with sweat, twisted helmet on the wearer's head, back and forth slippage of the helmet during play, etc.).

A texture of the textured surface 151 may be defined by a maximum thickness differential MTD (or “amplitude”) of the textured surface 151 measured from the pits/valleys 152 to the peak/ridges 153. Such MTD times the surface area occupied by the skin 150 may define a total texture volume (TTV), which includes a percentage of volume of material and a complementary percentage of volume of air. In at least some embodiments, the texture of the textured surface 151 has a TTV with a percentage of volume of material of between about 60% and about 90%. In some cases the texture of the textured surface 151 has a TTV with a percentage of volume of material of between about 60% and about 80%, or between about 60% and 70%. Having a TTV with a percentage of volume of material of at least 60% may provide greater comfort in some embodiments.

The textured surface may include dimples (e.g. rounded, squared, honeycombed, randomly generated and uneven as opposed to smooth, etc.). A denser dimples pattern over the textured surface 151 may provide a more uniform pressure distribution on the wearer's head for a given force. In other words, a greater density of support/contact points between the textured surface 151 and the wearer's head may provide greater comfort. The texture of the textured surface 151 may be defined by signs of mean curvature and/or Gaussian curvatures in some embodiments. Mean curvature and/or Gaussian curvature may be measured based on a three-dimensional scan of a surface and a pixel analysis conducted using algorithms of a CAD software, representing a “heat map”, for example. Different colors of such “heat map” may indicate different mean curvature values or Gaussian curvature value. As one possibility, a tile of material (e.g. 15 mm by 15 mm) with the textured surface 151 may be taken as a test surface, on which the analysis is conducted. Examples of textures are discussed below with respect to some embodiments. The textured surface 151 may also be defined by friction values. Such friction values may be measured on samples based on ISO or ASTM standards.

Exemplary textures are illustrated in FIGS. 6 to 17 , each having different parameters (dimple geometry, density, mean curvature, etc.). Although numerous possible textures were evaluated by the inventors, it was particularly found that, in accordance with one possible embodiment of the liner 130, the textures illustrated at FIGS. 15 to 17 may provide a greater balance between comfort and slippage. Features of these best suited textures identified at FIGS. 15 to 17 will be described in further details below.

FIG. 15 illustrates a texture of a textured surface 151 that is defined by a random noise function, which forms unevenly distributed and sized peaks and valleys with a generally even MTD. A magnified view of cross-section A1 of the texture of FIG. 15 is illustrated at FIG. 15A. As shown, the MTD progressively decreases out towards the edges of the surface (i.e. from 100% MTD to 0% MTD). While illustrated on a square tile for simplicity, the progressively decreasing MTD at the edges may also characterize the surface areas of the head facing surface 131 occupied by skin 150. In other words, the texture of the textured surface of the skin 150 may fade out along a junction between skinless areas and skin areas. In some cases, such fade out margin may extend over a distance between 2 and 13 times the MTD, in some cases, between 2 and 5 times the MTD.

FIG. 16 illustrates a texture of the textured surface 151 that is defined by an array of evenly distributed dimples, or array of rounded peaks and valleys. Magnified views of cross-sections B1, B2 of the texture of FIG. 16 are illustrated at FIGS. 16A-16B. As shown, the texture has a generally even MTD, which progressively decreases out towards the edges of the surface. While illustrated on a square tile for simplicity, the progressively decreasing MTD at the edges may also characterize the surface areas of the head facing surface 131 occupied by skin 150. In other words, the texture od the textured surface of the skin 150 may fade out along a junction between skinless areas and skin areas. In some cases, such fade out margin may extend over a distance between 2 and 13 times the MTD, in some cases, between 2 and 5 times the MTD.

FIG. 17 illustrates a texture of the textured surface 151 that is defined by an array of evenly distributed dimples, or array of rounded peaks and valleys, similar to that shown in FIG. 16 , but finer. Magnified views of cross-sections C1, C2 of the texture of FIG. 17 are illustrated at FIGS. 17A-17B. As shown, the texture has a generally even MTD, which progressively decreases out towards the edges of the surface. While illustrated on a square tile for simplicity, the progressively decreasing MTD at the edges may also characterize the surface areas of the head facing surface 131 occupied by skin 150. In other words, the texture od the textured surface of the skin 150 may fade out along a junction between skinless areas and skin areas. In some cases, such fade out margin may extend over a distance between 2 and 13 times the MTD, in some cases, between 2 and 5 times the MTD.

In a particular embodiment, such as with the texture of FIG. 15 , 10%±5% of the surface area of the skin 150 on the head facing surface 131 of the liner 130 has a mean curvature value of H=0, 35%±5% with a mean curvature value of H>0, and 50%±5% with a mean curvature value of H<0 (provided the total % values=100%).

In some cases, such as with the textures of FIGS. 16 and 17 , between about 25% and 55% of the surface area of the skin 150 on the head facing surface 131 of the liner 130 has a mean curvature H value of H=0, which corresponds to a flat surface area, between about 25% and about 45% with H<O, and/or between about 15% and about 30% with H>0.

In a particular embodiment, such as with the texture of FIG. 16 , 50%±5% of the surface area of the skin 150 on the head facing surface 131 of the liner 130 has a mean curvature value of H=0, 20%±5% with a mean curvature value of H>0, and 25%±5% with a mean curvature value of H<0 (provided the total % values=100%).

In another particular embodiment, such as with the texture of FIG. 17 , 30%±5% of the surface area of the skin 150 on the head facing surface 131 of the liner 130 has a mean curvature value of H=0, 30%±5% with a mean curvature value of H>0, and 40%±5% with a mean curvature value of H<0 (provided the total % values=100%).

The above described features of the best suited textures may provide an optimal balance between comfort and slippage of the liner 130 on the wearer's head, where too much slippage may provide more helmet movement on the wearer's head. Too much slippage which may cause undesirable discomfort for the wearer during the practice of the activity, as mentioned above. Other textures, although not visually or geometrically identical to those shown in FIGS. 15 to 17 , may alternately be used provided that these alternate textures provide similar levels of comport, grip, and/or resistance to slippage due to sweat, etc.

Other aspects of the liner 130 of the present disclosure will be described with reference to another embodiment of the liner 130, shown in FIGS. 18A to 18D. For sake of conciseness and simplicity, similar features will not be described again and will keep the same reference numerals as that of the previous figures.

As shown, the paddings 130F, 130T, 130C, 130R, 130S have portions with a lattice structure 140 having thicker struts 141 than other portions thereof. For instance, in an embodiment, the lattice structure 140, although manufactured as a continuous part from the head facing surface 131 to the outer surface 132, the struts 141 of the lattice structure 140 have a diameter gradient from the outer shell side to the head side of the liner 130. Such diameter gradient may facilitate the manufacturing and assist in balancing stiffness versus weight, for instance when diameter/thickness of the struts 141 may be selectively reduced to reduce weight of the overall padding when a desired stiffness is already obtained at a given location of the liner 130/padding(s). In addition to or instead of such diameter gradient in a thickness-wise direction of the liner 130, the lattice structure 140 at the peripheral surface 133 may have thicker (greater average diameter or thickness) struts 141 than the struts 141 within the corpus of the liner 130. This may facilitate the manufacturing using additive manufacturing techniques. In some embodiments, the lattice structure 140 that is closer to the head side of the liner 130 has a Voronoi geometry, and the lattice structure 140 on the outer shell side of the liner 130 has the serpentine geometry. Other combinations may be contemplated in other embodiments.

In some embodiments, the lattice structure 140 with a Voronoi geometry may be more comfortable for the wearer than a lattice structure 140 having a serpentine geometry, when in direct contact with the wearer's head, for instance. In some cases, the Voronoi geometry may not provide the desired strength-to-weight ratio. In such cases, where high strength is desirable, a denser Voronoi geometry could become heavy, e.g. heavier than a lattice structure 140 with a serpentine geometry for a similar/equivalent strength. The serpentine geometry may provide a higher strength to weight ratio than a Voronoi geometry at a given density, in some embodiments. A lattice structure 140 having a serpentine geometry may be provided in regions of the liner 130 that are not in contact with the wearer's skin/head to achieve weight savings, which may compensate for weight penalties resulting from zones that would require a denser Voronoi geometry, for comfort purposes. As such, in at least some embodiments, the lattice structure 140 which may contact the wearer's head (at the head facing surface 131) when the helmet 100 is donned has a Voronoi geometry, or at least a predominately Voronoi geometry composition. In embodiments and designs where the dedicated volume/space for the liner 130 in a thickness-wise direction allows it, the lattice structure 140 may include an under-layer having a serpentine geometry, which may contribute to weight savings, instead of having only lattice structure 140 with a Voronoi geometry. In some embodiments, the lattice structure 140 underneath the skin(s) 150 may have a serpentine geometry as the skin(s) 150 interfacing with the wearer's head may interface therewith. As such, a same level of comfort may be achieved while having a comparatively higher strength-to-weight ratio of such synthetized liner 130.

Accordingly, in at least one particular embodiment, the lattice structure 140 of the liner 130 may be composed of a predominately Voronoi geometry in regions that are in contact with, or which may become in contact with, the skin of the wearer—e.g. in first zones 161. In other region where the liner thickness permits greater thickness, such as the second zones 162, an underlying of serpentine lattice geometry may be provided for improved weight savings. Such a thicker liner including serpentine lattice geometry may be less desirable in regions that require a thinner liner, such as on the sides in a hockey helmet for example. In an alternate embodiment, however, it remains possible to entirely eliminate the Voronoi cell structures within the lattice entirely, whereby the lattice is formed by serpentine lattice geometry, with the skins provided thereon for abutment with the wearer's skin.

FIGS. 18C-18D show selected volumes of the respective paddings 130F, 130T, 130C, 130R, 130S, with such volumes defining zones of the lattice structure 140 of the paddings 130F, 130T, 130C, 130R, 130S having specific mechanical properties different from the lattice structure 140 at other adjacent zones.

In the embodiment shown:

-   -   the front padding 130F has a first zone 161F defining a layer of         the padding 130F stacked on a second zone 162F of the padding         130F. The lattice structure 140 in the first zone 161F has a         Voronoi geometry and in the second zone 162F has a serpentine         geometry, for example. The front padding 130F has a third zone         163F extending along and forming the peripheral surface 133 of         the front padding 130F, the third zone 163F extending across the         entire thickness of the front padding 130F, from the head facing         surface 131 to the outer surface 132, the lattice structure 140         in the third zone 163F has a Voronoi geometry and is denser than         that of the lattice structure 140 in the first zone 161F;     -   the top padding 130T has a first zone 161T defining a layer of         the padding 130T stacked on a second zone 162T of the padding         130T. The lattice structure 140 in the first zone 161T has a         Voronoi geometry and in the second zone 162T has a serpentine         geometry having a stiffness in a thickness-wise direction         greater than the lattice structure 140 in the first zone 161T,         for example. The layer formed by the first zone 161T being         closer to the wearer's head than the layer formed by the second         zone 162T. The first zone 161T forms at least part of the head         facing surface 131 of the top padding 130T;     -   the crown padding 130C has a first zone 161C defining a layer of         the padding 130C stacked on a second zone 162C of the padding         130C. The lattice structure 140 in the first zone 161C has a         Voronoi geometry and in the second zone 162C has a serpentine         geometry, for example. The layer formed by the first zone 161C         being closer to the wearer's head than the layer formed by the         second zone 162C. The first zone 161C forms at least part of the         head facing surface 131 of the crown padding 130C;     -   the side paddings 130S has a single zone 161S defining the         paddings 130S. The lattice structure 140 in the single zone 161S         has a Voronoi geometry, for example;     -   and the rear padding 130R has a first zone 161R, a second zone         162R and at least a third zone 163R, each defining parts of the         padding 130R extending from the head facing surface 131 to the         outer surface 132. The lattice structure 140 in each zones 161R,         162R, 163R has a Voronoi geometry. In the first zone 161R, at         least some of the struts 141 are thinner (average thickness)         than the struts 141 in the second and third zones 162R, 163R,         for example.

FIGS. 18E-18I show respective cross-sections of the front padding 130F, the top padding 130T, the crown padding 130C, the side paddings 130S and the rear padding 130R of FIGS. 18A-18D. The cross-sections of the front padding 130F, the top padding 130T, the crown padding 130C and the rear padding 130R are taken along the meridional plane SPH and the cross-section of the side padding 130S is taken along plane C (see FIG. 18B). As shown:

-   -   in FIG. 18E, the cross-section of the front padding 130F shows a         ribbon 135 of the serpentine geometry of the second zone 162F         that is separated from the Voronoi geometry of the first zone         161F by the boundary layer 136 (discussed above). A plurality of         struts 141 of the Voronoi geometry connect to the boundary layer         136 at various locations within the padding 130F. The ribbon 135         has a varying width W where the thickness of the padding 130F         varies;     -   in FIG. 18F, similar to that shown in FIG. 18E, the         cross-section of the top padding 130T has a ribbon 135 of the         serpentine geometry in the second zone 162T that is shown has         having a varying width W, and separated from the struts 141 of         the Voronoi geometry of the first zone 161T by boundary layer         136. The boundary layer 136 extends also at the outer surface         132;     -   in FIG. 18G, similar to that shown in FIG. 18E, the         cross-section of the crown padding 130C, has a ribbon 135 of the         serpentine geometry in the second zone 162C that is shown has         having a varying width W, and separated from the struts 141 of         the Voronoi geometry of the first zone 161C by boundary layer         136. The boundary layer 136 extends also at the outer surface         132;     -   in FIG. 18H, the cross-section of one of the side paddings 130S         shows an entirety of the lattice structure 140 across the         thickness of the padding 130S with a Voronoi geometry; and     -   in FIG. 18I, the cross-section of the rear padding 130R shows         the Voronoi geometry in the first and second zones 161R, 162R.         As indicated previously, at least some of the struts 141 in the         first zone 161R are thinner than the struts 141 in the second         zone. Such thinner struts 141 (e.g. see those pointed with the         reference lines) extend substantially parallel (skewed by less         than 10 degrees relative to the head facing surface 131 radially         offset therewith).

The zones of the paddings 130F, 130T, 130C, 130R, 130S discussed above may each have unique mechanical properties (e.g. stiffness, damping, viscosity, density, geometries, etc.) that are dependent upon the respective locations of the paddings 130F, 130T, 130C, 130R, 130S within the helmet 100, where such locations may define different maximal thicknesses of the paddings or available spaces dedicated for the liner 130 within the cavity 122, as a possibility. For instance, the lattice structure 140 at a selected location within the helmet 100 may have a greater proportion of the struts 141 oriented normal to the inner surface 123 of the outer shell and/or the wearer's head. Such orientation of the struts 140 may provide greater stiffness against impact directed normal to the outer surface 121 of the outer shell 120, in some embodiments.

Returning to FIG. 18B, the paddings 130F, 130T, 130C, 130R, 130S have skin 150 extending along a periphery of the head facing surface 131, between the periphery and the skinless surface area. At least some of the paddings have the skin 150 extending on at least part of the peripheral surface 133. As shown, a peripheral edge 134 defined at a junction between the head facing surface 131 and the peripheral surface 133 is covered by the skin 150.

Most, if not all of the skinless surface areas of the respective paddings 130F, 130T, 130C, 130R, 130S is surrounded by surface area(s) occupied by the skin 150. As shown, at least some of the paddings have a skinless surface area that is surrounded by the skin 150 such that the three-dimensional lattice 140 is visible (i.e. exposed) in the skinless area from an interior of the helmet 100. As shown, the skinless surface area is defined by a plurality of separate portions of skinless surface area. For instance, as shown, the top padding 130T, side paddings 130S and crown padding 130C each define a plurality of portions of skinless surface areas that are surrounded by a surface area occupied by the skin 150.

Other aspects of the liner 130 of the present disclosure will be described with reference to another embodiment of the liner 130, shown in FIGS. 19A to 19C. For sake of conciseness and simplicity, similar features will not be described again and will keep the same reference numerals as that of the previous figures.

As shown, the paddings 130F, 130T, 130C, 130R, 130S have a different shape. As one aspect, the front and side paddings 130F, 130S of the liner 130 define a continuous part. In other words, the front and side paddings 130F, 130S are integral such as to form a single piece. As another aspect, the skin 150 on the paddings 130F, 130T, 130C, 130R, 130S is positioned differently, and proportions of skinless surface areas are different (FIG. 19B).

As shown in FIG. 19B, the paddings 130F, 130T, 130C, 130R, 130S include hinges 170F, 170R defined in their respective lattice structure 140 and/or skin 150. Such hinges 170F, 170R may be referred to as a plurality of kerf cuts defined in the paddings 130F, 130T, 130C, 130R, 130S to allow, or at least facilitate, deformation of the paddings 130F, 130T, 130C, 130R, 130S in a predetermined bending pattern to conform to the domed inner surface 123 of the outer shell 120. In the depicted embodiment, some of the hinges are defined in the head facing surface 131 of the paddings 130F, 130T, 130C, 130R, 130S, and are referred to as Front hinges (see hinges 170F in FIG. 19B). Some of the hinges are defined in the outer surface 132 of the paddings 130F, 130T, 130C, 130R, 130S, and are referred to as Rear hinges (see hinges 170R in FIG. 19B). For a piece of material having a curvature in at least two directions, as for the liner 130/padding(s) to conform to the domed inner surface 123 and/or cavity 122, it may be desirable to have hinges 170F, 170R, defined in both the head facing surface 131 and the outer surface 132 as it may allow a better fit of the paddings within the outer shell 120, in some embodiments. Yet, it may be desirable to minimize the amount of hinges 170F defined in the head facing surface 131 such as to minimise “discontinuities” in the head facing surface 131. This may provide a more comfortable fit of the liner 130 on the wearer's head. As such, at least in some embodiments, the liner 130, or one or more of the paddings 130F, 130T, 130C, 130R, 130S may have more rear hinges 170R than front hinges 170F. For instance, in an embodiment, there may be at least twice more rear hinges 170R than front hinges 170F. Other ratios to minimize the amount of front hinges 170F may be contemplated.

The hinges 170F, 170R extend along directions allowing suitable folding of the paddings 130F, 130T, 130C, 130R, 130S when the paddings 130F, 130T, 130C, 130R, 130S are assembled within the cavity 122 of the outer shell 120. As shown, for instance, the continuous front and side paddings 130F, 130S of the liner 130 include hinges 170F defined in the head facing surface 131 and hinges 170R defined in the outer surface 132, with at least part of the hinges 170F in the head facing surface that extend transverse to the hinges 170R in the outer surface 170R.

The hinges 170F, 170R may have various depth, sizes, shape and/or dimensions, depending on the embodiments. For instance, in some cases, the hinges 170F, 170R have a maximal depth of about 30% of the thickness of the padding(s) 130F, 130T, 130C, 130R, 130S., in some other cases of about 50%, and in some case even more than 50%. A majority of the hinges 170F may extend through the skinless area(s) of the liner 130/padding(s) 130F, 130T, 130C, 130R, 130S. This may facilitate the manufacturing of the liner 130/padding(s) 130F, 130T, 130C, 130R, 130S, and/or allow a more flexible hinging, for instance.

Manufacturing of such paddings with hinges 170F, 170R may be facilitated, and less expensive to produce, as they may take less time to produce, using 3-D printing techniques, for instance. In some cases, 3-D printing techniques may “grow” the liner 130 one layer by one layer, starting from a flat plane at the bottom of a tray containing the liquid substrate to be transformed into a solid structure. Hinges 170F, 170R in the paddings 130F, 130T, 130C, 130R, 130S may allow the manufacturing of such paddings 130F, 130T, 130C, 130R, 130S on a flat plane in less time, by reducing the amount of layers to be printed to obtain a final product. As such, the paddings 130F, 130T, 130C, 130R, 130S having hinges 170F, 170R may lie on a flat plane such that, in an unfolded state, most if not all of the inner or outer surfaces 131, 132 of such paddings may face towards such flat plane. In an embodiment, having such hinges 170F, 170R may allow the manufacturing of the liner 130 as a single, continuous part, with hinges 170F, 170R defined at selected locations to facilitate assembly of the liner 130 within the cavity 122 of the outer shell 120. Locations of the hinges 170F, 170R on each padding may vary depending on the embodiments. In some embodiments, the hinges 170F, 170R are selectively located to reduce wrinkles in the material of the padding(s), for instance wrinkles that may be defined in the skin 150 on the head facing surface 131 while the padding(s) is/are bent to conform to the domed inner surface 123 of the outer shell 120.

FIG. 19C, show selected volumes of the respective paddings 130F, 130T, 130C, 130R, 130S shown in the embodiment of FIG. 19B, with such volumes defining zones of the lattice structure 140 of the paddings 130F, 130T, 130C, 130R, 130S having specific mechanical properties different from the lattice structure 140 at other adjacent zones.

In the embodiment shown:

-   -   the front padding 130F and the side paddings 130S are formed as         an integral part. The portion corresponding to the front padding         130F has a first zone 161F and a second zone 162F. The lattice         structure 140 in the first zone 161F and the second zone 162F         has a Voronoi geometry with different densities. The first zone         161F defines the peripheral surface 133 and the peripheral edge         134 adapted to extend along the wearer's forehead, and part of         the peripheral surface 133 of the padding 130F that faces the         top padding 130T. The second zone 162F extending from the first         zone 161F and towards the top padding 130T. The second zone 162F         forming at least part of the peripheral surface 133 of the         padding 130F facing the top padding 130T. The portion         corresponding to the side paddings 130S each define a third zone         163F forming an entirety of the side paddings 130S. The lattice         structure in the first, second and third zones 161F, 162F, 163F         all have a Voronoi geometry with different strut thicknesses.         All the zones 161F, 162F, 163F in this embodiment extend across         the entire thickness of the front padding 130F/side paddings         130S, from the head facing surface 131 to the outer surface 132;     -   the top padding 130T has a first zone 161T adjacent a second         zone 162T. The first and second zones 161T, 162T extend along a         meridional plane SPH of the helmet 100 (see FIG. 20 ), i.e. the         meridional plane SPH intersects with the first and second zones         161T, 162T. The first zone 161T includes part of the peripheral         surface 133 of the padding 130T that faces the front padding         130F. The second zone 162T includes part of the peripheral         surface 133 of the padding 130T that faces the crown padding         130C. The top padding 130T has a third zone 163T defined on         opposite sides of the first and second zones 161T, 162T,         relative to the meridional plane SPH. The third zone 163T         includes part of the peripheral surface 133 of the padding 130T         that faces the front and side paddings 130F, 130S, and the crown         padding 130C. The lattice structure 140 in the first and second         zones 161T, 162T has a Voronoi geometry with different strut         thicknesses. The lattice structure 140 in the third zone 163T         has a Voronoi geometry with cells 143 smaller than in the         lattice structure 140 of the first and second zones 161T, 162T;     -   the crown padding 130C has one zone 161C with the lattice         structure 140 having a Voronoi geometry with cells 143 of         non-constant dimensions. The struts 141 of the lattice structure         140 in the crown padding 130C are thicker at the periphery of     -   the padding 130C than the struts 141 within the corpus of the         padding 130C; and the rear padding 130R has a first zone 161R         and a second zone 162R. The first zone 161R defines a bottommost         portion of the rear padding 130R, including the peripheral         surface 133 in such bottommost portion of the rear padding 130R         that faces towards a neck of the wearer (when in the worn helmet         100). The first zone 161R also defines a central portion of the         rear padding 130R and part of the peripheral surface 133 of the         rear padding 130R that faces the crown padding 130C. The second         zone 162R extends outwardly from the first zone 161R and         includes the peripheral surface 133 of the padding 130R that         faces the side paddings 130S and part of the peripheral surface         133 of the padding 130R that faces the crown padding 130C. The         lattice structure 140 in the first zone 161R has a Voronoi         geometry, with the struts 141 at the periphery of the padding         130R thicker than the struts 141 within the corpus of the         padding 130R. The lattice structure 140 in the second zone 162R         has a Voronoi geometry with the cells 143 smaller than that of         the lattice structure 140 in the first zone 161R.

FIGS. 19D-19G show respective cross-sections of the front padding 130F, the top padding 130T, the crown padding 130C, and the rear padding 130R of FIGS. 19A-19C. The cross-sections are taken along the meridional plane SPH (see FIG. 19B). As shown:

-   -   in FIG. 19D, the cross-section of the front padding 130F shows         the Voronoi geometry of the lattice structure 140 across an         entirety of the thickness of the padding 130F, except for the         skin 150 in areas of the padding 130F where present. A skinless         area is defined between the peripheral edge 134 and part of the         head facing surface 131 extending from that peripheral edge 134         covered by skin 150, and another part of the head facing surface         131 having the skin 150. As shown, on a part of the padding         130F, the skin 150 extends from the head facing surface 131, to         the peripheral surface 133 all the way to a junction between the         peripheral surface 133 and the outer surface 132 of the padding         130F;     -   in FIG. 19E, the cross-section of the top padding 130T shows the         Voronoi geometry of at least one of the zones 161T, 162T, 163T.         A majority of the head facing surface 131 along the         cross-section is skinless. The skin 150 covers the peripheral         edge 134 on opposite sides of the padding 130T. An hinge 170R in         the outer surface 132 is also visible;     -   in FIG. 19F, the cross-section of the crown padding 130C shows         the Voronoi geometry of the lattice structure 140 across the         thickness of the padding 130C. The peripheral edge 134 on one         side of the padding 130C is covered by skin 150. Two hinges 170R         defined in the outer surface 132 are visible; and     -   in FIG. 19G, the cross-section of the rear padding 130R shows         the Voronoi geometry of the lattice structure 140, with some         struts 141 at the outer surface 132 thicker than struts 141 of         the Voronoi geometry located closer to the head facing surface         131 (see for instance struts 141 pointed with the reference         lines).

Referring to FIG. 19H, in the depicted embodiment, liner shims 175 interface between the outer shell 120 and the liner 130. A plurality of liner shims 175 are disposed within the cavity 122. The liner shims 175 may be secured in various suitable manners to the outer shell 120, for instance using fasteners or adhesive. The liner shims 175 may be sized and/or dimensioned to fit on the inner surface 123 of the outer shell 120 at locations devoid from vent holes VH. In other words, the liner shims 175 may not block the vent holes VH, whereby air flow through the vent holes VH could be hindered. The liner shims 175 disposed at respective locations within the cavity 122 may be made of different materials, or same materials having different mechanical properties (e.g. stiffness, damping, viscosity, density, etc.), depending on their respective locations within the cavity 122. For instance, it may be desirable to have softer liner shim(s) 175 at selected locations, as opposed to stiffer liner shim(s) 175 at other selected locations. In an embodiment, at least some of the liner shims 175 are made of a material denser than the lattice structure 140 of the liner 130, where under application of a static force on such liner shims 175, the material of the liner shims 175 may compress more than the liner 130 under the same static force at a force application point, in proportion of their respective thicknesses.

For instance, as shown, the liner shims 175 disposed at a top most portion of the cavity 122, closer to a top of the wearer's head and on sides of the cavity 122, closer to temples of the wearer's head are made of non-Newtonian material, such as the D30® material commercialized by D30 Lab. Such material may allow for added impact energy absorption/attenuation relative to other types of materials, such as expanded polypropylene (EPP), for instance. As shown, a liner shim 175 is located at a front of the cavity 122, close to a forehead of the wearer when the helmet is worn. In the embodiment shown, such liner shim 175 is made of vinyl nitrile (VN) foam material. As shown a liner shim 175 is disposed at a rear of the cavity 122. Such liner shim 175 is made of EPP foam. Other materials may be contemplated in other embodiments for the liner shims 175. In such embodiments where liner shims 175 are present between the outer shell 120 and the liner 130 (not shown in FIG. 19H), the liner 130 having a plurality of paddings or may not have an outer surface 132 with a shape conforming/corresponding to that of the inner surface 123 of the outer shell 120, which may facilitate assembly within the outer shell 120 and/or facilitate fitting and/or manufacturing of the liner 130.

In some embodiments, the skin 150 may define gutters to channel sweat away from the wearer's eye. Referring to FIG. 20 , such gutters 180 are defined in the front padding 130F. The gutters 180 define a sweat inlet 181 defined by a skinless surface area in the head facing surface 131 adapted to extend along a superciliary arch of the wearer's head. As shown, the peripheral edge 134 of the liner 130 at the front padding 130F is covered by the skin 150. Such skin 150 on the peripheral edge 134 extends over a distance from the peripheral edge 134 on the head facing surface 131. The skin 150 extending between the peripheral edge 134 and the sweat inlet 181 defines a sweat barrier in that sweat coming down from the forehead region of the wearer's head when the helmet 100 is worn may deviate through the inlet 181, where fluid circulation is more easily achieved, through the open lattice structure 140, and blocked (or at least limited) from flowing further down towards the wearer's eyes by the presence of the skin 150 between the inlet 181 and the peripheral edge 134 of the liner 130 in contact with the wearer's forehead. In some embodiments, the inlet 181 may be dimensioned to limit the distance between the skinless area defining the inlet 181 and the peripheral edge 134, to minimize the surface area occupied by the skin 150, for increased breathability, for instance. In such embodiments, it may be desirable to maintain at least the peripheral edge 134 covered by the skin 150 to obtain such sweat barrier. As such, in contact with the wearer's forehead, the skinned peripheral edge 134 at the front of the liner 130 (at the front padding 130F) may provide such sweat barrier by blocking the sweat from dripping further down towards the wearer's eyes and deviate such sweat towards the inlet 181 and through the open lattice structure 140. In the depicted embodiment, a pair of inlets 181 circumferentially spaced apart from each other on opposite sides of a meridional plane SPH of the helmet 100 by skin 150 extending in between them. In other embodiments, there may be a single elongated inlet 181 extending continuously along the peripheral edge 134 of the liner 130 at the front padding 130F, with such single inlet 181 intersecting with the meridional plane SPH of the helmet 100. Such single elongated inlet 181 may maximize the surface area along the peripheral edge 134 of the front padding 130F that capture sweat.

As shown, the gutters 180 define a sweat outlet 182 in a segment of the peripheral surface 133 of the liner 130 free of the skin 150 (i.e. a skinless surface area) on opposite sides of a face of the wearer, more specifically on opposite sides of the eyes of a wearer. In the depicted embodiment, such location of the sweat outlet 182 is closer from the sides of the helmet 100 than from the meridional plane SPH of the helmet 100. The gutters 180, through the inlet(s) 181 may capture and redirect the sweat flowing down towards the eyes of the wearer, at least partially, during play. In some embodiments, such as shown, the gutter 180 may define a central gutter outlet 183 in a skinless surface area of the peripheral surface 133 of the liner 130 located in a zone intersecting the meridional plane SPH of the helmet 100. Such central gutter outlet 183 may be adapted to be aligned between the eyes of the wearer when the helmet is donned correctly. In the depicted embodiment, the central gutter outlet 183 is fluidly connected to the sweat inlet(s) 181 through the open lattice structure 140 of the front padding 130F. The central gutter outlet 183 is defined in another segment (other than the segments defining the outlets 182) of the peripheral surface 133 of the liner 130 free of the skin 150, where the central outlet 183 is separated from the sweat outlet(s) 182 by a portion of the skin 150 extending on the peripheral surface 133 of the liner 130 between the sweat outlet(s) 182 and the central gutter outlet 183.

The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. For instance, other high strength-to-weight ratio structures may be contemplated instead of or in addition to the lattice structure 140 having a serpentine structure as described above. Such other structures could be combined with a lattice structure 140 having a Voronoi geometry as described above, and/or the skin 150. It is to be understood that any specific value provided herein, including but not limited to the percentage of the surface of the skins having a specific mean curvature value of the texture, the percentage volumes of material of the textured surfaces, the proportions of skinless surface area of the inner surface of the liner, etc. may include a limited amount of variance, due to tolerances, manufacturing limitations, and/or other factors, without departing from the scope and intent of the present disclosure, as will be appreciated by a person of ordinary skill in the art. The term “about”, when used in this context, is understood to refer to such variances. Yet further modifications could be implemented by the person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology. 

1. A helmet adapted to be worn on a head of a wearer, comprising: an outer shell including a first shell portion and a second shell portion displaceable relative to one another to adjust a size of the helmet; and an energy-attenuating inner liner disposed within the outer shell, the energy-attenuating inner liner including a first liner portion disposed within the first shell portion and a second liner portion disposed within the second shell portion, the first and second liner portions being displaceable relative to each other when the first and second shell portions are displaced; wherein the first liner portion and the second liner portion each comprise a three-dimensional lattice formed of a plurality of cells and at least one liner skin integrally formed with the three-dimensional lattice, the liner skin defining part of a head facing surface of the energy-attenuating inner liner, the liner skin adapted to contact the head of the wearer, the liner skin covering less than an entirety of three-dimensional lattice of each of the first and second liner portions along the head facing surface to define exposed regions of the three-dimensional lattice free of the liner skin.
 2. The helmet of claim 1, wherein the first liner portion and the second liner portion each define a separate padding forming parts of the energy-attenuating inner liner.
 3. The helmet of claim 1, wherein the liner skin extends along a periphery of the first liner portion and the second liner portion.
 4. The helmet of claim 1, wherein the liner skin protrudes from an adjacent one of the exposed regions of the three-dimensional lattice free of the liner skin.
 5. The helmet of claim 4, wherein the liner skin has a radial dimension taken in a direction normal to the head facing surface, at least part of the radial dimension defined radially inward from the adjacent one of the exposed regions of the three-dimensional lattice free of the liner skin.
 6. The helmet of claim 1, wherein the liner skin defines an innermost surface of the energy-attenuating inner liner radially offset from the exposed regions of the three-dimensional lattice free of the liner skin.
 7. The helmet of claim 1, wherein the energy-attenuating inner liner has an outer shell facing surface and peripheral surfaces extending between the head facing surface and the outer shell facing surface, the head facing surface and the peripheral surfaces defining a peripheral edge of the energy-attenuating inner liner at a junction thereof, the liner skin forming the peripheral edge. 8.-10. (canceled)
 11. The helmet of claim 1, wherein the liner skin has a textured surface defining an array of valleys and peaks.
 12. The helmet of claim 11, wherein the textured surface has a maximum thickness differential (MTD) measured from a deepest pit to a highest peak, the MTD times a surface area of the head facing surface of the liner occupied by the skin defines a total texture volume (TTV) including a percentage of volume of material and a complementary percentage of volume of air, the percentage of volume of material being of about at least 60%.
 13. (canceled)
 14. The helmet of claim 1, wherein the liner includes at least a front padding adapted to cover at least a forehead and/or a frontal portion of the head of the wearer, the frontal padding defining a sweat gutter configured to channel sweat from between the liner and the forehead of the head of the wearer when the helmet is donned to a region of the liner adapted to be located on a side of a face of the wearer laterally rearward of an eye of the wearer when the helmet is donned, the sweat gutter having: a sweat inlet defined by a segment of the skinless surface area surrounded by the liner skin in the head facing surface, the sweat inlet positioned at a location of the liner adapted to extend along a superciliary arch of the head of the wearer, and a sweat outlet defined by in a segment of a peripheral surface of the liner free of liner skin, the segment of the peripheral surface closer from a side of the helmet than from a sagittal plane of the helmet.
 15. A helmet adapted to be worn on a head of a wearer, the helmet comprising: an outer shell defining an outermost impact protection structure of the helmet, the outer shell defining a cavity to receive the head of the wearer when the helmet is worn, the outer shell including a domed inner surface facing towards the cavity and an opposite outer surface; and a liner disposed in the cavity, the liner having a head facing surface and an outer surface opposite the head facing surface, the outer surface facing towards the domed inner surface of the outer shell, the liner comprising a three-dimensional lattice formed of a plurality of cells and at least one liner skin integrally formed with the three-dimensional lattice, the liner skin forming part of the head facing surface of the liner, the liner skin covering less than an entirety of the three-dimensional lattice so as to define a skinless surface area on the head facing surface of the liner, the liner adapted to at least attenuate an impact energy transferred to the head of the wearer from a force received by the helmet.
 16. The helmet of claim 15, wherein the outer shell has a plurality of shell members movable relative to each other to adjust a size and/or fit of the helmet on the head of the wearer, wherein the plurality of shell members of the outer shell include a front shell member and a rear shell member slidably engaged with each other such that movement of the front shell member and the rear shell member relative to each other adjust at least a longitudinal size of the cavity.
 17. (canceled)
 18. The helmet of claim 15, wherein the outer surface of the liner contacts the inner surface of the outer shell and has a shape complementary to that of the inner surface of the outer shell.
 19. (canceled)
 20. The helmet of claim 15, wherein the domed inner surface of the outer shell has areas having a profile protruding towards the head of the wearer when the helmet is worn, the liner skin defining areas of the head facing surface radially offset from the areas having the profile protruding towards the head of the wearer such that the skinless surface area is tangentially offset from the areas having the profile protruding towards the head of the wearer. 21.-24. (canceled)
 25. The helmet of claim 15, wherein the skinless surface area is surrounded by the liner skin such that the three-dimensional lattice is exposed in the skinless surface area from an interior of the helmet.
 26. (canceled)
 27. The helmet of claim 15, wherein the liner skin extends along a periphery of the head facing surface, between the periphery and the skinless surface area, and the liner has a peripheral surface extending between the head facing surface and the outer surface, a junction between the head facing surface and the peripheral surface defining a peripheral edge, the liner skin covering the peripheral edge, the three dimensional lattice visible along the peripheral edge on the peripheral surface.
 28. (canceled)
 29. The helmet of claim 15, wherein the liner skin protrudes from an adjacent portion of the liner that is in the three-dimensional lattice, and the liner skin has a radial dimension taken in a direction normal to the head facing surface, at least part of the radial dimension defined radially inward from the adjacent one of the exposed regions of the three-dimensional lattice free of the liner skin. 30.-40. (canceled)
 41. The helmet of claim 15, wherein a texture of the textured surface defined by the array of valleys and peaks defines evenly distributed dimples, the textured surface has a maximum thickness differential (MTD) measured from a deepest pit to a highest peak, the textured surface having the MTD progressively decreasing out towards edges of the surface area of the head facing surface of the liner occupied by the liner skin.
 42. (canceled)
 43. The helmet of claim 41, wherein the textured surface defines a fade out margin extending over a distance between 2 and 13 times the MTD. 44.-48. (canceled)
 49. The helmet of claim 15, wherein the three dimensional lattice includes a network of struts interconnected at nods, the struts having a diameter gradient in a thicknesswise direction of the liner from the outer surface to the head facing surface of the liner, the struts adjacent the outer surface having a smaller average diameter than that of the struts adjacent the head facing surface.
 50. The helmet of claim 15, wherein the liner has a peripheral surface extending between the head facing surface and the outer surface, the three dimensional lattice includes a network of struts interconnected at nods, the struts at the peripheral surface being thicker than the struts within a corpus of the liner between the head facing surface and the outer surface.
 51. The helmet of claim 15, wherein the three dimensional lattice includes a network of struts interconnected at nods, the struts originating from respective ones of the nods extend away therefrom in different directions, the three-dimensional lattice having a greater proportion of the struts oriented normal to the domed inner surface of the outer shell at a first selected location within the helmet than at a second selected location within the helmet. 52.-53. (canceled)
 54. The helmet of claim 15, wherein the liner includes a plurality of paddings forming respective parts of the head facing surface of the liner, the liner includes at least a front padding adapted to cover at least a forehead and/or a frontal portion of the head of the wearer, aha rear padding adapted to cover at least a rear portion of the head of the wearer, a top padding adapted to cover at least a top portion of the head of the wearer, a crown padding adapted to cover at least a crown portion of the head of the wearer, and side paddings adapted to cover at least respective side portions of the head of the wearer. 55.-57. (canceled)
 58. The helmet of claim 54, wherein the front padding has a first zone defining a layer of the front padding stacked on a second zone of the front padding, the three-dimensional lattice in the first zone having a Voronoi geometry and the three-dimensional lattice in the second zone has a serpentine geometry.
 59. The helmet of claim 54, wherein the rear padding has a first zone, a second zone and at least a third zone, each defining parts of the rear padding and extending from the head facing surface to the outer surface of the liner, wherein the three dimensional lattice includes a network of struts interconnected at nods, the three dimensional lattice in the first zone, the second zone and the third zone having a Voronoi geometry, at least in the first zone the struts being thinner than the struts in the second and third zones.
 60. The helmet of claim 54, wherein the top padding has a first zone defining a layer of the top padding stacked on a second zone of the top padding, the three-dimensional lattice in the first zone having a Voronoi geometry and the three-dimensional lattice in the second zone has a serpentine geometry having a stiffness in a thickness-wise direction greater than the three-dimensional lattice in the first zone.
 61. The helmet of claim 54, wherein the crown padding has a first zone defining a layer of the crown padding stacked on a second zone of the crowd padding, the three dimensional lattice in the first zone having a Voronoi geometry and the three dimensional lattice in the second zone having a serpentine geometry. 62.-63. (canceled)
 64. The helmet of claim 54, wherein the front padding include hinges defined in the head facing surface and in the outer surface, at least part of the hinges in the head facing surface extends transverse to the hinges in the outer surface.
 65. (canceled)
 66. The helmet of claim 15, wherein the three-dimensional lattice includes first zones composed of cells having a predominately Voronoi geometry and second zones composed of cells having a predominately serpentine geometry.
 67. (canceled)
 68. The helmet of claim 15, further comprising a plurality of liner shims disposed within the cavity, the plurality of liner shims secured to the domed inner surface of the outer shell, the plurality of liner shims contacting the outer surface of the liner. 69.-70. (canceled)
 71. The helmet of claim 14, wherein the sweat gutter is a first sweat gutter, the front padding having a second sweat gutter, the second sweat gutter fluidly connected to the sweat inlet of the first sweat gutter through the front padding, the second sweat gutter having a central sweat outlet defined in another segment of the peripheral surface of the liner located in a zone intersecting the sagittal plane of the helmet, the central outlet separated from the sweat outlet of the first sweat gutter by a portion of the liner skin extending on the peripheral surface of the liner between the sweat outlet of the first sweat gutter and the central outlet. 